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Noyes–Whitney Equation
Arthur Amos Noyes (September 13, 1866 – June 3, 1936) was an American chemist, inventor and educator. He received a PhD in 1890 from Leipzig University under the guidance of Wilhelm Ostwald. He served as the acting president of MIT between 1907 and 1909 and as Professor of Chemistry at the California Institute of Technology from 1919 to 1936. "Although he Noyeslaboratory at MIT was like an institute in its intramural funding (from Carnegie Institute of Washington and Noyes's patent royalties), Noyes recruited many of his disciples as undergraduates and took a deep interest in undergraduate engineering education, both at MIT and later at Caltech. John Servos, "The industrial relations of science: Chemical Engineering at MIT, 1900-1939", Isis, 71 (1980) 531-549. Roscoe Gilkey Dickinson was one of his famous students. Noyes was a major influence both on the educational philosophy of the core curriculum of Caltech as well as in the negotiations leading to the creation of the N ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Newburyport, Massachusetts
Newburyport is a coastal city in Essex County, Massachusetts, United States, northeast of Boston. The population was 18,289 at the 2020 census. A historic seaport with vibrant tourism industry, Newburyport includes part of Plum Island. The mooring, winter storage, and maintenance of recreational boats, motor and sail, still contribute a large part of the city's income. A Coast Guard station oversees boating activity, especially in the sometimes dangerous tidal currents of the Merrimack River. At the edge of the Newbury Marshes, delineating Newburyport to the south, an industrial park provides a wide range of jobs. Newburyport is on a major north-south highway, Interstate 95. The outer circumferential highway of Boston, Interstate 495, passes nearby in Amesbury. The Newburyport Turnpike (U.S. Route 1) still traverses Newburyport on its way north. The Newburyport/Rockport MBTA commuter rail from Boston's North Station terminates in Newburyport. The earlier Boston and Maine Ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
George Ellery Hale
George Ellery Hale (June 29, 1868 – February 21, 1938) was an American solar astronomer, best known for his discovery of magnetic fields in sunspots, and as the leader or key figure in the planning or construction of several world-leading telescopes; namely, the 40-inch refracting telescope at Yerkes Observatory, 60-inch Hale reflecting telescope at Mount Wilson Observatory, 100-inch Hooker reflecting telescope at Mount Wilson, and the 200-inch Hale reflecting telescope at Palomar Observatory. He also played a key role in the foundation of the International Union for Cooperation in Solar Research and the National Research Council, and in developing the California Institute of Technology into a leading research university. Early life and education George Ellery Hale was born on June 29, 1868, in Chicago, Illinois, to William Ellery Hale and Mary Browne.Adams 1939, p. 181. He is descended from Thomas Hale of Watton-on-Stone, Hertfordshire, England, whose son emigrate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1866 Births
Events January–March * January 1 ** Fisk University, a historically black university, is established in Nashville, Tennessee. ** The last issue of the abolitionist magazine '' The Liberator'' is published. * January 6 – Ottoman troops clash with supporters of Maronite leader Youssef Bey Karam, at St. Doumit in Lebanon; the Ottomans are defeated. * January 12 ** The ''Royal Aeronautical Society'' is formed as ''The Aeronautical Society of Great Britain'' in London, the world's oldest such society. ** British auxiliary steamer sinks in a storm in the Bay of Biscay, on passage from the Thames to Australia, with the loss of 244 people, and only 19 survivors. * January 18 – Wesley College, Melbourne, is established. * January 26 – Volcanic eruption in the Santorini caldera begins. * February 7 – Battle of Abtao: A Spanish naval squadron fights a combined Peruvian-Chilean fleet, at the island of Abtao, in the Chiloé Archipelago of southern Chile. * February 13 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion Layer
In electrochemistry, the diffusion layer, according to IUPAC, is defined as the "region in the vicinity of an electrode where the concentrations are different from their value in the bulk solution. The definition of the thickness of the diffusion layer is arbitrary because the concentration approaches asymptotically the value in the bulk solution". The diffusion layer thus depends on the diffusion coefficient (D) of the analyte and for voltammetric measurements on the scan rate (V/s). It is usually considered to be some multiple of (Dt)1/2 (where 1/t = scan rate). The value is physically relevant since the concentration of solute varies according to the expression derived from Fick's Laws: \tfrac=erf(\tfrac) When x=\sqrt, the concentration is approximately 52% of the bulk concentration: erf(1/2)=0.520499878... At slow scan rates, the diffusion layer is large, on the order of micrometers, whereas at fast scan rates the diffusion layer is nanometers in thickness. The relationship ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion Coefficient
Diffusivity, mass diffusivity or diffusion coefficient is a proportionality constant between the molar flux due to molecular diffusion and the gradient in the concentration of the species (or the driving force for diffusion). Diffusivity is encountered in Fick's law and numerous other equations of physical chemistry. The diffusivity is generally prescribed for a given pair of species and pairwise for a multi-species system. The higher the diffusivity (of one substance with respect to another), the faster they diffuse into each other. Typically, a compound's diffusion coefficient is ~10,000× as great in air as in water. Carbon dioxide in air has a diffusion coefficient of 16 mm2/s, and in water its diffusion coefficient is 0.0016 mm2/s. Diffusivity has dimensions of length2 / time, or m2/s in SI units and cm2/s in CGS units. Temperature dependence of the diffusion coefficient Solids The diffusion coefficient in solids at different temperatures is generally found ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diffusion
Diffusion is the net movement of anything (for example, atoms, ions, molecules, energy) generally from a region of higher concentration to a region of lower concentration. Diffusion is driven by a gradient in Gibbs free energy or chemical potential. It is possible to diffuse "uphill" from a region of lower concentration to a region of higher concentration, like in spinodal decomposition. The concept of diffusion is widely used in many fields, including physics (particle diffusion), chemistry, biology, sociology, economics, and finance (diffusion of people, ideas, and price values). The central idea of diffusion, however, is common to all of these: a substance or collection undergoing diffusion spreads out from a point or location at which there is a higher concentration of that substance or collection. A gradient is the change in the value of a quantity, for example, concentration, pressure, or temperature with the change in another variable, usually distance. A change in c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Area
The surface area of a solid object is a measure of the total area that the surface of the object occupies. The mathematical definition of surface area in the presence of curved surfaces is considerably more involved than the definition of arc length of one-dimensional curves, or of the surface area for polyhedra (i.e., objects with flat polygonal faces), for which the surface area is the sum of the areas of its faces. Smooth surfaces, such as a sphere, are assigned surface area using their representation as parametric surfaces. This definition of surface area is based on methods of infinitesimal calculus and involves partial derivatives and double integration. A general definition of surface area was sought by Henri Lebesgue and Hermann Minkowski at the turn of the twentieth century. Their work led to the development of geometric measure theory, which studies various notions of surface area for irregular objects of any dimension. An important example is the Minkowski cont ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharmacy
Pharmacy is the science and practice of discovering, producing, preparing, dispensing, reviewing and monitoring medications, aiming to ensure the safe, effective, and affordable use of medicines. It is a miscellaneous science as it links health sciences with pharmaceutical sciences and natural sciences. The professional practice is becoming more clinically oriented as most of the drugs are now manufactured by pharmaceutical industries. Based on the setting, pharmacy practice is either classified as community or institutional pharmacy. Providing direct patient care in the community of institutional pharmacies is considered clinical pharmacy. The scope of pharmacy practice includes more traditional roles such as compounding and dispensing of medications. It also includes more modern services related to health care including clinical services, reviewing medications for safety and efficacy, and providing drug information. Pharmacists, therefore, are experts on drug therapy and a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvation
Solvation (or dissolution) describes the interaction of a solvent with dissolved molecules. Both ionized and uncharged molecules interact strongly with a solvent, and the strength and nature of this interaction influence many properties of the solute, including solubility, reactivity, and color, as well as influencing the properties of the solvent such as its viscosity and density. If the attractive forces between the solvent and solute particles are greater than the attractive forces holding the solute particles together, the solvent particles pull the solute particles apart and surround them. The surrounded solute particles then move away from the solid solute and out into the solution. Ions are surrounded by a concentric shell of solvent. Solvation is the process of reorganizing solvent and solute molecules into solvation complexes and involves bond formation, hydrogen bonding, and van der Waals forces. Solvation of a solute by water is called hydration. Solubility of solid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rate (mathematics)
In mathematics, a rate is the ratio between two related quantities in different units. If the denominator of the ratio is expressed as a single unit of one of these quantities, and if it is assumed that this quantity can be changed systematically (i.e., is an independent variable), then the numerator of the ratio expresses the corresponding ''rate of change'' in the other (dependent) variable. One common type of rate is "per unit of time", such as speed, heart rate and flux. Ratios that have a non-time denominator include exchange rates, literacy rates, and electric field (in volts per meter). In describing the units of a rate, the word "per" is used to separate the units of the two measurements used to calculate the rate (for example a heart rate is expressed "beats per minute"). A rate defined using two numbers of the same units (such as tax rates) or counts (such as literacy rate) will result in a dimensionless quantity, which can be expressed as a percentage (for example ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equation
In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign . The word ''equation'' and its cognates in other languages may have subtly different meanings; for example, in French an ''équation'' is defined as containing one or more variables, while in English, any well-formed formula consisting of two expressions related with an equals sign is an equation. ''Solving'' an equation containing variables consists of determining which values of the variables make the equality true. The variables for which the equation has to be solved are also called unknowns, and the values of the unknowns that satisfy the equality are called solutions of the equation. There are two kinds of equations: identities and conditional equations. An identity is true for all values of the variables. A conditional equation is only true for particular values of the variables. An equation is written as two expressions, connected by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
